Friction false-twist device

ABSTRACT

In a false twist device of the friction type, a main friction element is formed with a yarn contact surface vaulted on all sides and having at least one annular groove transverse of its axis of rotation and a secondary friction element has at least one annular disc extending transversely with respect to its rotation axis and mating with the groove. Guide means feed and withdraw the yarn transversely with respect to the axis of rotation of the main friction element.

United States Patent [191 Horvath et al.

[5 FRICTION FALSE-TWIST DEVICE [75] Inventors: Lajos Horvath, Wallisellen; Arnold Steck, Wattwil, both of Switzerland [73] Assignee: Heberlein & Co. AG, Wattwi],

Switzerland [22] Filed: Sept. 24, 1974 [21] Appl. No.: 508,832

[30] Foreign Application Priority Data Oct. 1, 1973 Switzerland 13760/73 Feb. 14, 1974 Switzerland 1 2083/74 May 27, 1974 Switzerland 7211/74 [52] US. Cl. 57/774 [51] Int. Cl. DOIH 7/92; DOZG l/O4 [58]. Field of Search 57/77.377.45

[56] References Cited UNITED STATES PATENTS 3,287,890 1 H1966 McIntosh et al 57/77/1- 51 Nov. 18, 1975 3,762,149 10/1973 Raschle 57/774 3,811.258 5/1974 Batsch 57/774 X 3,820,317 6/1974 Raschle 57/774 FOREIGN PATENTS OR APPLICATIONS 854,781 11/1960 United Kingdom 57/774 Primary E.raminerDonald E. Watkins Attorney, Agent, or Firm-Fitz'patrick, Cella, Harper & Scinto [57] ABSTRACT In a false twist device of the friction type, a main friction element is formed with a yarn contact surface vaulted on all sides and having at least one annular groove transverse of its axis of rotation and a secondary friction element has at least one annular disc extending transversely with respect to its rotation axis and mating with the groove. Guide means feed and withdraw the yarn transversely with respect to the axis of rotation of the main friction element.

38 Claims, 5 Drawing Figures U..S.-Patent Nov. 18,1975 Sheet10f2 3,919,833

US. Patent Nov. 18, 1975 Sheet2of2 3,919,833'

FRICTION FALSE-TWIST DEVICE This invention relates to apparatus for imparting false twist to textile yarns and, more particularly, to such apparatus wherein the twist is imparted by bringing the yarn into contact with rotating surfaces.

Devices for the production of false-twist in textile yarns are known by means of which the twist is imparted to the yarn by direct frictional contact with rotating surfaces. Thus, for example, a device is disclosed in British Pat. specification No. 854,781 which consists of two parallel rotatable shafts on each of which there is arranged a number of circular discs, the rims of which overlap mutually and penetrate into the interstices between the discs on the other shaft. The diameters of the discs are such that the whole disc arrangement of each shaft is barrel-shaped which permits good yarn application into the vaulted cuneal gaps. In each of the two disc arrangements, the central discs, or at least their rims, may consist of a material having a high friction coefficient with respect to the textile yarn and the discs at the ends of the disc arrangements, or at least their rims, may consist of a material with high wear-resistance, for example steel. When false-twisting textile yarns of synthetic materials such as polyamides or polyesters, the preferred material with a high friction coefficient is a synthetic material on a polyurethane base which however is subject to high wear, so that the respective discs or their rims must be exchanged frequently.

We have conceived by the present invention a device whereby we are able to avoid the foregoing disadvantage. Essentially, our device comprises friction elements arranged on two parallel rotation shafts, the circumferences of which elements partially, mutually overlap. The device of the present invention is characterized in that it consists of a main friction element of wear-resistant material which comprises a yarn contact surface vaulted on all sides and at least one annular groove extending transversely with respect to its rotation axis, as well as a secondary friction element with at least one circular or annular disc extending transversely with respect to its rotation axis, the rim or rims of which mate with the annular groove or grooves of the main friction element. Guide means are provided for feeding and withdrawing the textile yarn transversely with respect to the rotation axis of the main friction element.

The fact that the yarn is fed and withdrawn transversely with respect to the rotation axis of the main friction element makes it possible for the yarn to be practically only in contact with thevaulted surface of the main friction element and to be pressed against the same by yarn tension. lmparting the false-twist is accordingly effected mainly through frictional contact with the vaulted surface of the main friction element; whereas, the circular or annular disc or discs of the secondary friction element which mate with the annular groove or grooves of the main friction element primarily serve the purpose of yarn guiding and of stabilization of the yarn path, and only secondarily to impart false-twist. The disc or discs of the secondary friction element, or its rim or rims, may preferably consist of a material having a high friction coefficient with respect to textile yarns of synthetic material, for example polyurethane synthetic material, in which case rapid wear of the disc rims does not occur, but on the other hand,

2 the production of false-twist by the discs is all the same assisted in a most effective manner.

According to one aspect of our invention, the main friction element may preferably have the shape of a sphere, of an ellipsoid or a shape similar to that of an ellipsoid. With such friction elements having a surface vaulted on all sides, soft feeding and withdrawal of the yarn can be achieved which reduces tension variations.

The main friction element may be formed of an aluminum base element which has previously been rough ened as by sand-jet treatment, or it may consist of metal oxide ceramic material, materials with a ceramic coating, cast iron or a compound material of silicium car bide and polyurethane synthetic material.

Experience has shown that, in the texturizing of synthetic endless yarns, the use of main friction elements made from the abovementioned materials provides the advantages mentioned when used with a wide-range of yarn structures. However, when the yarn consists of relatively thin monofilaments of the appropriate titer of the single filaments of 2 or 3 dtex, for example, we have observed that superior results can be achieved by forming the main friction element, or at least the outer surface thereof, of polyurethane synthetic material, such as a resilient cross-linking polyurethane sold under the trademark VULKOLLAN. Due to the relatively high friction coefficients of polyurethane synthetic materials with respect to textile yarns of synthetic material, a better driving effect on such yarn, and therefore a high twist density, are achievable along with a substantial reduction in breakages.

There has thus been outlined rather broadly, the more important features of the invention in order that the detailed description thereof that follows may be better understood and in order that the present contribution to the art may be better appreciated. There are, of course, additional features of the invention that will be described hereinafter and which will form the subject of the claims appended hereto. Those skilled in the art will appreciate that the conception upon which this disclosure is based may readily be utilized as a basis for the designing of other structures for carrying out the several purposes of the invention. It is important, there fore, that the claims be regarded as including such equivalent construction as do not depart from the spirit and scope of the invention.

Specific embodiments of the invention have been chosen for purposes of illustration and description, and are shown in the accompanying drawings forming a part of the specification wherein:

FIG. 1 is a central longitudinal cross-section through a first embodiment of the invention;

FIG. 2 is a top elevation of the embodiment according to FIG. 1; and

FIGS. 3, 4 and 5 are central longitudinal sections through three further embodiments of the invention.

According to FIGS. 1 and 2, the rotation shafts 1 and 2 of the two friction elements are drivable by means of a driving device (not shown) in the same sense of rotation. On the rotation shaft 1, we arrange a spherical main friction element 3 which is provided with three annular grooves 4, 5 and 6, the central groove 5 being positioned in the equatorial zone of the sphere 3. On rotation shaft 2, we provide the cylindrical secondary friction element on which are arranged annular discs 8, 9 and 10, and these are maintained at certain distances from each other by spacer rings 22 and 23 and in place on the shaft by terminal rings 21 and 24. The rims of discs 8, 9 and 10 project into or mate with the annular grooves 4, 5 and 6. The spherical shaped main friction element 3 consists of hard-anodized aluminum, roughened by sand-jet treatment; and the annular discs 8, 9 and 10 consist of polyurethane synthetic material, and their diameter is somewhat smaller than the diameter of the main friction element 3. The extremities 1, l, of the rotation shaft 1, which extend beyond the main friction element on both sides, serve as thread-guides for the textile yarn 11 being fed to and withdrawn from the device. The rotation shafts 1, 2 are shiftable in a direction perpendicular with respect to their longitudinal axes so that projection of the annular discs into the annular grooves can be adjusted, as desired.

FIG. 3 illustrates a similar embodiment in which, however, the main friction element 3 comprises only two annular grooves 4, 5; and the secondary friction element consists of a cylindrical polyurethane element 12 comprising two annular discs 13, 14.

The main friction element may also comprise, instead of one piece, two spherical or ellipsoid calotte-shaped members and a circular disc 14 between which there are arranged spacer sockets whereby the annular grooves 4 and 5 are formed.

FIG. 4 illustrates a further embodiment in which the main friction element 3 consists of two half-spheres l7, 18, with a spacer socket 19 of reduced diameter inserted therebetween by which the annular groove 4 is formed. The secondary friction element consists of a cylindrical polyurethane element which comprises only one annular disc 16. Removal of yarn 11 is effected by deviation by means of roller 20 rotatable about its axis in the same direction as the feed direction.

As has been stated, the main friction element may have the shape of a sphere, of an ellipsoid or a similar shape, and the textile yarn which is fed to the rotation axis of the main friction element is applied to the vaulted surface of the main friction element and is pressed against the same by the yarn tension. Imparting of false-twist is therefore mainly effected by frictional contact of the yam with this surface. In operation, as will be understood by those skilled in the art, the yarn passes over the vaulted surface on the side on which it has been fed until it reaches its summit in high-twisted condition, is practically immediately untwisted after passing the summit and thereafter passes over the vaulted surface in detwisted condition until it reaches the point at which it is removed.

We have observed that, when texturing endless yarns of synthetic material, such as polyester yarns of polyethylene terephtalate and polyamide yarns of polyhexamethylene adipamide, for example, the use of main friction elements formed from the above-mentioned materials, under certain circumstances such as inadequate roughness of the material, may permit too much yarn slippage to occur because of their relatively low friction coefficients with respect to certain synthetic yarn materials so that the twist density which can be obtained is insufficient.

We have found that this problem can be resolved by forming the part of the main friction element, which forms the vaulted yarn contact surface, of two different materials, as shown in FIG. 5.

In this case, preferably, the part of the main friction element over the yarn contact surface of which the yarn passes in high-twisted condition may consist of a material the friction coefficient of which, with respect to the yarn material, is higher than the friction coefficient of the part of the main friction element over the yarn contact surface of which the yarn passes in untwisted condition.

An example of this aspect of our invention is explained in more detail with reference to FIG. 5 from which it will be seen that the main friction element 3, arranged on the rotation shaft 1, consists of two halfspheres 21, 22 with intermediate spacer socket 19 by which the annular groove 4 is formed. The secondary friction element arranged on rotation shaft 2 consists of a cylindrical element 15 of polyurethane synthetic material which comprises only one annular disc 16. The half-sphere 21 over the surface of which the yarn 11 passes in high-twisted condition consists of polyurethane synthetic material, and the half-sphere over the surface of which the yarn 11 passes in untwisted condition consists of porcelain. Because of the relatively high friction coefficient of polyurethane synthetic material, a good yarn driving effect, and therefore a higher twist density, can be achieved in the high-twisted yarn. Since no more twist is applied to the yarn during its passage of the half-sphere 22, it is not a disadvantage that porcelain has a relatively low friction coefficient with respect to the synthetic material.

- We believe that the construction and operation of our novel friction false twist device will now be understood and that the advantages thereof will be fully appreciated by those persons skilled in the art.

We claim:

1. Friction false-twist device for textile yarns, comprising two parallel rotation shafts each supporting a friction element, the circumferences of which mutually, partially overlap, characterized by a main friction element formed with at least one yarn contact surface vaulted on all sides and with at least one annular groove and a secondary friction element formed with at least one circular disc, the rim of which mates with the annular groove of the main friction element, and guiding means for feeding and withdrawing the yarn transversely with respect to the rotation axis of the main friction element.

2. Device according to claim 1, characterized in that at least the rim of the secondary friction element consists of a material having a high friction coefficient with respect to the textile yarn.

3. Device according to claim 2, characterized in that at least the rim of the secondary friction element consists of polyurethane synthetic material.

4. Device according to claim 1, characterized in that the main friction element has the shape of a sphere.

5. Device according to claim 1, characterized in that the main friction element has the shape of an ellipsoid or the like.

6. Device according to claim 1, characterized in that the main friction element is a roughened base-element of aluminum having an oxide coating.

7. Device according to claim 4, characterized in that the main friction element is a roughened base-element of aluminum having an oxide coating.

8. Device according to claim 5, characterized in that the main friction element is a roughened base-element of aluminum having an oxide coating.

9. Device according to claim 1, characterized in that the main friction element consists of metal oxide ceramic material.

10. Device according to claim 4, characterized in that the main friction element consists of metal oxide ceramic material. I

11. Device according to claim 5, characterized in that the main friction element consists of metal oxide ceramic material.

12. Device according to claim 1, characterized in that the main friction element consists of cast iron.

13. Device according to claim 4, characterized in that the main friction element consists of cast iron.

14. Device according to claim 5, characterized in that the main friction element consists of cast iron.

15. Device according to claim 1, characterized in that the main friction element consists of a compound material of silicium carbide and of polyurethane synthetic material.

16. Device according to claim 4, characterized in that the main friction element consists of a compound material of silicium carbide and of polyurethane synthetic material.

17. Device according to claim 5, characterized in that the main friction element consists of a compound material of silicium carbide and of polyurethane synthetic material.

18. Device according to claim 1, characterized in that the annular grooves in the main friction element are formed by two spherical or ellipsoidal calotteshaped members with at least one circular disc and spacer socket arranged between the discs and the spherical or ellipsoidal members.

19. Device according to claim 4, characterized in that the annular grooves in the main friction element are formed by two spherical or ellipsoidal calotteshaped members with at least one circular disc and spacer socket arranged between the discs and the spherical or ellipsoidal members.

20. Device according to claim 5, characterized in that the annular grooves in the main friction element are formed by two spherical or ellipsoidal calotteshaped members with at least one circular disc and spacer socket arranged between the discs and the spherical or ellipsoidal members.

21. Device according to claim 1, characterized in that the annular groove in the main friction element is formed by two spherical calotte-shaped members and by a spacer socket inserted therebetween.

22. Device according to claim 4, characterized in that the annular groove in the main friction element is formed by two spherical calotte-shaped members and by a spacer socket inserted therebetween.

23. Device according to claim 5, characterized in that the annular groove in the main friction element is formed by two spherical callotte-shaped members and by a spacer socket inserted therebetween.

24. Device according to claim 1, characterized in that the diameter of the disc or discs of the secondary friction elements at least approximately corresponds to the greatest diameter of the main friction element.

25. Device according to claim 1, characterized in that the ends of the rotation shaft of the main friction element, which extend beyond the latter, serve as guide means for yarn feed and removal.

26. Device according to claim 1, characterized in that the rotation shafts of the friction elements are shiftable perpendicularly with respect to the longitudinal axes of the friction elements.

27. Device according to claim 1, characterized in that at least the surface of the main friction element consists of polyurethane synthetic material.

28. Device according to claim 4, characterized in that at least the surface of the main friction element consists of polyurethane synthetic material.

29. Device according to claim 5, characterized in that at least the surface of the main friction element consists of polyurethane synthetic material.

30. Friction false-twist device according to claim 1, characterized in that the part of the main friction ele' ment which forms the vaulted yarn contact surface consists of two different materials.

31. Friction false-twist device according to claim 4, characterized in that the part of the main friction element which forms the vaulted yarn contact surface consists of two different materials.

32. Friction false-twist device according to claim 5, characterized in that the part of the main friction element which forms the vaulted yarn contact surface consists of two different materials.

33. Friction false'twist device according to claim 21, characterized in that the two calotte-shaped members which form the vaulted yarn contact surface consists of two different materials.

34. Device according to claim 30, characterized in that the part of the main friction element over the yarn contact surface of which the yarn passes in high-twisted condition, consists of a material the friction coefficient of which with respect to the yarn mate rial is higher than the friction coefficient of the part of the main friction element over the yarn contact surface of which the yarn passes in untwisted condition.

35. Device according to claim 30, characterized in that the part of the main friction element over the yarn contact surface of which the yarn passes in high-twisted condition consists of polyurethane synthetic material.

36. Device according to claim 34, characterized in that the part of the main friction element over the yarn contact surface of which the yarn passes in high-twisted condition consists of polyurethane synthetic material.

37. Device according to claim 30, characterized in that the part of the main friction element over the yarn contact surface of which the yarn passes in untwisted condition consists of ceramic material.

38. Device according to claim 34, characterized in that the part of the main friction element over the yarn contact surface of which the yarn passes in untwisted condition consists of ceramic material. 

1. Friction false-twist device for textile yarns, comprising two parallel rotation shafts each supporting a friction element, the circumferences of which mutually, partially overlap, characterized by a main friction element formed with at least one yarn contact surface vaulted on all sides and with at least one annular groove and a secondary friction element formed with at least one circular disc, the rim of which mates with the annular groove of the main friction element, and guiding means for feeding and withdrawing the yarn transversely with respect to the rotation axis of the main friction element.
 2. Device according to claim 1, characterized in that at least the rim of the secondary friction element consists of a material having a high friction coefficient with respect to the textile yarn.
 3. Device according to claim 2, characterized in that at least the rim of the secondary friction element consists of polyurethane synthetic material.
 4. Device according to claim 1, characterized in that the main friction element has the shape of a sphere.
 5. Device according to claim 1, characterized in that the main friction element has the shape of an ellipsoid or the like.
 6. Device according to claim 1, characterized in that the main friction element is a roughened base-element of aluminum having an oxide coating.
 7. Device according to claim 4, characterized in that the main friction element is a roughened base-element of aluminum having an oxide coating.
 8. Device according to claim 5, characterized in that the main friction element is a roughened base-element of aluminum having an oxide coating.
 9. Device according to claim 1, characterized in that the main friction element consists of metal oxide ceramic material.
 10. Device according to claim 4, characterized in that the main friction element consists of metal oxide ceramic material.
 11. Device according to claim 5, characterized in that the main friction element consists of metal oxide ceramic material.
 12. Device according to claim 1, characterized in that the main friction element consists of cast iron.
 13. Device according to claim 4, characterized in that the main friction element consists of cast iron.
 14. Device according to claim 5, characterized in that the main friction element consists of cast iron.
 15. Device according to claim 1, characterized in that the main friction element consists of a compound material of silicium carbide and of polyurethane synthetic material.
 16. Device according to claim 4, characterized in that the main friction element consists of a compound material of silicium carbide and of polyurethane synthetic material.
 17. Device according to claim 5, characterized in that the main friction element consists of a compound material of silicium carbide and of polyUrethane synthetic material.
 18. Device according to claim 1, characterized in that the annular grooves in the main friction element are formed by two spherical or ellipsoidal calotte-shaped members with at least one circular disc and spacer socket arranged between the discs and the spherical or ellipsoidal members.
 19. Device according to claim 4, characterized in that the annular grooves in the main friction element are formed by two spherical or ellipsoidal calotte-shaped members with at least one circular disc and spacer socket arranged between the discs and the spherical or ellipsoidal members.
 20. Device according to claim 5, characterized in that the annular grooves in the main friction element are formed by two spherical or ellipsoidal calotte-shaped members with at least one circular disc and spacer socket arranged between the discs and the spherical or ellipsoidal members.
 21. Device according to claim 1, characterized in that the annular groove in the main friction element is formed by two spherical calotte-shaped members and by a spacer socket inserted therebetween.
 22. Device according to claim 4, characterized in that the annular groove in the main friction element is formed by two spherical calotte-shaped members and by a spacer socket inserted therebetween.
 23. Device according to claim 5, characterized in that the annular groove in the main friction element is formed by two spherical callotte-shaped members and by a spacer socket inserted therebetween.
 24. Device according to claim 1, characterized in that the diameter of the disc or discs of the secondary friction elements at least approximately corresponds to the greatest diameter of the main friction element.
 25. Device according to claim 1, characterized in that the ends of the rotation shaft of the main friction element, which extend beyond the latter, serve as guide means for yarn feed and removal.
 26. Device according to claim 1, characterized in that the rotation shafts of the friction elements are shiftable perpendicularly with respect to the longitudinal axes of the friction elements.
 27. Device according to claim 1, characterized in that at least the surface of the main friction element consists of polyurethane synthetic material.
 28. Device according to claim 4, characterized in that at least the surface of the main friction element consists of polyurethane synthetic material.
 29. Device according to claim 5, characterized in that at least the surface of the main friction element consists of polyurethane synthetic material.
 30. Friction false-twist device according to claim 1, characterized in that the part of the main friction element which forms the vaulted yarn contact surface consists of two different materials.
 31. Friction false-twist device according to claim 4, characterized in that the part of the main friction element which forms the vaulted yarn contact surface consists of two different materials.
 32. Friction false-twist device according to claim 5, characterized in that the part of the main friction element which forms the vaulted yarn contact surface consists of two different materials.
 33. Friction false-twist device according to claim 21, characterized in that the two calotte-shaped members which form the vaulted yarn contact surface consists of two different materials.
 34. Device according to claim 30, characterized in that the part of the main friction element over the yarn contact surface of which the yarn passes in high-twisted condition, consists of a material the friction coefficient of which with respect to the yarn material is higher than the friction coefficient of the part of the main friction element over the yarn contact surface of which the yarn passes in untwisted condition.
 35. Device according to claim 30, characterized in that the part of the main friction element over the yarn contact surface of which the yarn passes in high-twisted condition consists of polyurethane synthetic material.
 36. Device according to claim 34, characterized in that the part of the main friction element over the yarn contact surface of which the yarn passes in high-twisted condition consists of polyurethane synthetic material.
 37. Device according to claim 30, characterized in that the part of the main friction element over the yarn contact surface of which the yarn passes in untwisted condition consists of ceramic material.
 38. Device according to claim 34, characterized in that the part of the main friction element over the yarn contact surface of which the yarn passes in untwisted condition consists of ceramic material. 